Closes#4072
ty @Lusamine for checking japanese and english for complete clarity on this multi-year flip-flop.
historically, we used 0xFB.bit0 until jpn complained, changing it to 0xC9.bit4 to match the pk3 struct. Both were correct, and neither were correct.
With the new version of Visual Studio bringing C# 12, we can revise our logic for better readability as well as use new methods/APIs introduced in the .NET 8.0 BCL.